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Getting a Genetic Diagnosis from SPARK Answers a Family’s Questions

photo of a family

Marina Sarris

Date Revised: March 8, 2021

Mercedes Riggs watched her newborn as he struggled to breathe in the hospital neonatal intensive care unit (NICU). Evan was the bigger of her twins, who arrived early, but he worried her the most. He had a collapsed lung, and doctors noticed that his head was larger than expected.

A scan showed some differences in his brain structure, but it was functioning as it should, she says. Evan’s lung recovered, and he and twin sister, Audrey, came home from the hospital. But their mother had lingering concerns about Evan.

The babies grew, but Evan did not smile or sit up when Audrey did. At their first birthday, Evan was not crawling, walking, or talking. Months later, he was diagnosed with autism. Riggs thought about her pregnancy, the twin’s premature birth, and Evan’s problems in the NICU. Although she had followed the doctor’s orders, she couldn’t keep herself from wondering if she had done something that caused his developmental problems.

It would take several years — and an email from SPARK — before she could put those feelings aside.

The Winding Road to Diagnosis

Riggs, an attorney in Washington State, was perhaps more aware of developmental conditions than many parents. She has relatives on the autism spectrum. But she and her husband, Bobby, were puzzled by Evan’s delays and symptoms, which included sleep and gastrointestinal problems.

After his first birthday, Evan’s doctor referred him for early intervention services. After several months of therapies to improve his motor skills, Evan saw a developmental pediatrician. The doctor diagnosed him with autism, a condition that affects social and communication skills.

“I remember feeling kind of shocked,” Mercedes Riggs says. “Even though I had suspicions that something was going on that was possibly genetic, I wasn’t thinking autism. But I was also kind of relieved to know I wasn’t making a big deal out of nothing, and he did need these services and interventions.”

Evan, who is now 5, began receiving autism therapies as a toddler. But did autism explain all of his challenges?

His parents took him to see a specialist for genetic testing. Riggs remembers the doctor studying Evan’s face intently. People who have some genetic syndromes may have particular facial features. But the tests performed did not find anything significant, and the family left without a genetic diagnosis for Evan.

“I remember the doctor saying there are more extensive tests that can be done, but our insurance didn’t cover it, and to check back in a few years to see if our insurance would cover it at that point,” Riggs recalls.

Feelings of Guilt

Late at night Riggs researched autism, hoping to learn more ways to help Evan, who has limited speech.

Some questions stayed with her. She had been in a car accident while pregnant; had that affected Evan? Her doctor scheduled the twins to be born four weeks early, out of concern for Audrey’s growth. Did that hurt Evan? Did something go wrong when Evan was in the hospital NICU? None of those things were under her control, but still Riggs felt responsible. “There are all these feelings of guilt,” she says.

In an opinion article for Spectrum, autism researcher Helen Tager-Flusberg, Ph.D., addressed the guilt some mothers feel. “Too many women still hear from professionals, family and friends that perhaps they did or didn’t do something that caused their child to have autism. Many of the parents who have participated in our research over the years carry profound guilt about their child’s condition even when no one has directly accused them of contributing to it,” according to her article.1

Joining the SPARK Autism Study

Riggs heard about SPARK from friends. So when she saw a SPARK booth at an autism walk in Portland, Oregon, she stopped for information. She, husband Bobby, and both twins joined the study in 2017. They each contributed saliva samples for exome sequencing, a different type of genetic analysis than the one that Evan had done previously. Mercedes Riggs wanted to contribute to autism research, but she didn’t really expect to get a diagnosis for Evan.

Then, in 2019, she got an email from SPARK. She didn’t read it for a few days, thinking it was a routine notice. “Then I opened it up, and I texted my husband right away: ‘You won’t believe this.’ So I was really excited at that point.”

The email informed her that SPARK had news about Evan’s genetic analysis. Riggs arranged to get the information from a genetic counselor provided by SPARK. She and her husband gathered around their dining room table for the call. The counselor explained that Evan has a rare change to his CHD8 gene, a change that he did not inherit from his parents. Genetic changes that occur for the first time in a child are called “de novo,” meaning new.

As the Riggses learned about CHD8-related syndrome, some of Evan’s symptoms suddenly made sense. Many people with the syndrome have autism, a large head, frequent bouts of constipation followed by loose stools, and problems falling asleep. Children often have learning difficulties and need special education.2

What Can One Gene Do?

Our CHD8 gene plays an important role before we are born. The gene is active when a fetus’ brain cells are forming, and it controls other genes. “It’s been called a master regulator because it participates in this process of turning certain genes on and off, at the right time and at the right place, as the brain develops,” explains Brian O’Roak, Ph.D., a geneticist at Oregon Health and Science University who helped discover the gene’s link to autism.3

A small change to the CHD8 gene can affect the functioning of several thousand other genes, the researcher explains. “Not only is CHD8 a risk gene for autism, but many of the genes that it directly regulates are also risk genes for autism.” Scientists want to know if disruptions to all those genes, or just some of them, cause the changes in brain development that contribute to autism in CHD8-related syndrome, he says.

O’Roak met the Riggs family while filming a video about SPARK. In the video, he explains to Mercedes Riggs that nothing she did caused Evan’s condition.

Riggs has let go of her feelings of guilt. “Finding out that it was genetic, and that there was nothing that I could have done to cause or prevent it, was a big relief. It just really made me feel better,” she says.

Her husband agrees. “It was nice knowing that Evan’s autism happened from a natural process, and it wasn’t because of his stay in the NICU or some other factor that Mercedes and I caused,” Bobby Riggs says.

Finding a Community for Rare Conditions

The diagnosis from SPARK offered another benefit, Mercedes Riggs says. “Another reason I was relieved when we got the results back was I learned that we’re not alone. There are other people with the same genetic condition. There are other families dealing with the same developmental issues,” she says. She joined Facebook groups for people who have CHD8 changes, pouring over the information shared there. Her family joined Simons Searchlight, which promotes research into rare genetic conditions. The Searchlight CHD8 group has 17 families. Searchlight, like SPARK, is a project of the Simons Foundation Autism Research Initiative.

The family told Evan’s doctors about his genetic condition. Since some people who have CHD8-related syndrome have seizures, they took Evan for an electroencephalogram test for seizures. They were glad to know he does not have seizures.

Evan, meanwhile, delights his family with his cheerful nature. The kindergartener enjoys watching baking competition shows and football, and listening to music, especially artists Bruno Mars, Taylor Swift, and Radiohead.

He uses picture communication symbols, which are small pictures of objects and actions, to request things he wants. And he often wants salty snacks. He can speak some words. He recently asked for “Pirate Booty,” a crunchy snack, by name. When his parents say “no” to a treat, the 5-year-old football fan will try to do an end run around them. He will go to his twin, Audrey, or big sister, Sophie, to see if one of them will get him a snack.

One day last month, his mom was tickling him. Evan spoke one word: “Happy.”



  1. Tager-Flusberg H. Spectrum. Accessed April 22, 2020
  2. SPARK/Simons Searchlight CHD8-Related Syndrome Gene Guide
  3. O’Roak al. Nature 485, 246-250 (2012) PubMed